The present invention relates to a rail arrangement for guiding fittings inside guiding rails, particularly in aircraft, as well as to an aircraft comprising such a rail arrangement.
In most commercial aircraft the seat rows for passengers are arranged in the fuselage in such a way that the passengers are seated in the direction of flight, wherein the individual seat rows extend transversely to the direction of flight, and wherein several seat rows are arranged one behind the other in the direction of the longitudinal axis of the aircraft. Seat rows comprising two or three seats side-by-side are the norm. In larger aircraft, which most of the time can also comprise wider fuselages, in the meantime seats may also be installed in the middle along the longitudinal axis of the aircraft.
As a rule, seat rows are taken together to form groups or classes. There are usually two or three classes, which among other things may differ by a different seat pitch. In order to meet the interests of aircraft operators to convey as many passengers as possible, the seat pitch in aircraft can be adapted to the planned applications and to passenger numbers. For example, in economy class the seat pitch is shorter in the case of short flight distances than it is in long ones. In so-called holiday-travel aircraft, some aircraft, for example, have no business class and no first class, and consequently the seat pitch is the same throughout.
In order to optimally adapt the seat rows, as far as their number and their pitch are concerned, to the requirements of aircraft operators, as a rule the seat rows are held in rails. The seat rows can thus be placed in the rails and can, at least at predetermined spacing, be affixed along the longitudinal axis of the aircraft.
From the documents EP 1 544 105 A1, also published under U.S. Pat. No. 7,207,756 B2, and DE 103 60 807 A1, also published under U.S. Pat. No. 7,100,885 B2, for example seat rails are known that essentially comprise a C-shaped profile. This profile, which is rigidly connected to the fuselage floor, is open, in the form of a groove, towards the ceiling of the passenger cabin. In this arrangement the groove comprises widened regions at regular spacing so that a seat row can not just be threaded into the rail at the beginning or end of said rail, but can be threaded-in wherever these widened regions are present. In order to displace the seat rows, the affixation of the sliding pieces or fittings running in the rail are undone. Thereafter, the seat row is pushed to the intended position and is affixed anew.
However, it has been shown that as a result of dirt deposited in the rails the resistance during displacement of seat rows may increase over time. Such dirt may predominantly be food residues which together with drink containing sugar may form a very sticky deposit on the rail. Furthermore, this dirt may reach the area between the bottom of the profile and the fitting that slides on it. This in turn may increase friction resistance and, furthermore, may damage the rail and/or the fitting. In order to manually displace such a seat row, which as a rule is arranged on two rails that extend parallel to each other and are spaced apart from each other, an operator may need to apply more force than would be the case with a clean rail. Furthermore, the increased application of force and the irregular detachment of dirt may lead to a situation in which the seat row moves unevenly within each of its rails. This may result in canting or at times even in jamming of the fittings in the rails, in particular in the area of the widened regions in the rail profile.